[asan] In llvm.asan.globals, allow entries to be non-GlobalVariable and skip over them
Looks like there are valid reasons why we need to allow bitcasts in llvm.asan.globals, see discussion at https://github.com/apple/swift-llvm/pull/133. Let's look through bitcasts when iterating over entries in the llvm.asan.globals list.
Differential Revision: https://reviews.llvm.org/D55794
llvm-svn: 349544
diff --git a/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp b/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
index a5c64f3..769cd23 100644
--- a/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
+++ b/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
@@ -441,8 +441,11 @@
for (auto MDN : Globals->operands()) {
// Metadata node contains the global and the fields of "Entry".
assert(MDN->getNumOperands() == 5);
- auto *GV = mdconst::extract_or_null<GlobalVariable>(MDN->getOperand(0));
+ auto *V = mdconst::extract_or_null<Constant>(MDN->getOperand(0));
// The optimizer may optimize away a global entirely.
+ if (!V) continue;
+ auto *StrippedV = V->stripPointerCasts();
+ auto *GV = dyn_cast<GlobalVariable>(StrippedV);
if (!GV) continue;
// We can already have an entry for GV if it was merged with another
// global.
diff --git a/llvm/test/Instrumentation/AddressSanitizer/global_metadata_bitcasts.ll b/llvm/test/Instrumentation/AddressSanitizer/global_metadata_bitcasts.ll
new file mode 100644
index 0000000..324a04e
--- /dev/null
+++ b/llvm/test/Instrumentation/AddressSanitizer/global_metadata_bitcasts.ll
@@ -0,0 +1,13 @@
+; Test that the compiler doesn't crash when the llvm.asan.globals containts
+; an entry that points to a BitCast instruction.
+
+; RUN: opt < %s -asan -asan-module -asan-globals-live-support=1 -S
+
+target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-apple-macosx10.11.0"
+
+@g = global [1 x i32] zeroinitializer, align 4
+
+!llvm.asan.globals = !{!0, !1}
+!0 = !{[1 x i32]* @g, null, !"name", i1 false, i1 false}
+!1 = !{i8* bitcast ([1 x i32]* @g to i8*), null, !"name", i1 false, i1 false}